Outages of U.S. nuclear generating capacity averaged 3.1 gigawatts (GW) per day during the summer of 2023 (June 1 through August 31), a return to 2021 levels. Capacity outages this past summer exceeded those in summer 2022 by more than 25%. Nuclear capacity outages peaked in June because some reactors were still offline at the end of the spring refueling and maintenance season. June capacity outages averaged 6.1 GW per day and peaked at 8.3 GW.